Ive been looking into the necesities of home making a headphone measurement rig. Its a bit complicated once your talking ear size, shape, clamp, materials and so on.
It occurs to me that headphones.com stands as the leading educator on this topic, and is even actively adjusting the typical orientation or view of how we read these graphs. I feel like headphones.com should grassroots a measurement kit on their site, and offer compensations for the big boy rigs they use. Would just be nice to be able to do this from home, and if a proper compensation scheme could be worked up to match the other stuff, suddenly we can all make and coorborate measurements. Im sure it will start a bit messy, but the more people who measure and share, the more likely standardized fitment and measurement practices can be addressed. Just a thought as i feel this would be HUGE to the community. Measurementa are useful, but only to a point without being able to reference ones own gear.
That would be very cool, but a lot of work since every headphone would need its own compensation. Still, Resolve is already measuring headphones on multiple rigs. Whatâs one more?
Unfortunately the challenge is just that measurement rigs are expensive.
There are some clone options available of things like GRAS rigs, but given the fact that the IP infringement is a factor itâs not something that we would be able to actively recommend and certainly not something we could sell.
Additionally itâs worth noting that many of the clone options do not exactly match the real rigs so thatâs another issue even if you do get one.
It would be awesome if measurement rigs were much more affordable, and part of me hopes that with the potential demand amongst the audio community there may be an opportunity for B&K or GRAS to release something at a much more attainable price. But until then we are a little stuck with how things are.
(One of the main reasons theyâre so expensive is because thereâs a lot of money that goes into developing them, but then not a huge customer base. So whilst the cost to build a 5128 etc isnât all that much, they have to amortize very high development costs over a small number of sales. If they were to sell them cheaper there is now a market of audio enthusiasts for these products that didnât exist even a few years ago, but itâd be a huge risk for either company to take.)
Is there not something available that you can put in your ears and it measures it on your own head? so the 'different rigs/heads measure different be a non issue).
As if I was to invest in something like this it would be for personal use.
You can get in-ear mics, but they have their own challenges.
The measured response will only resemble the result obtained on your own head, and cannot be compared to measurements taken on either someone elseâs head, or a measurement rig/HATS since the head/pinna will be different.
In-ear mics either need to be blocked canal, which means you do not show any effects of how your ear canal itself is modifying sound, and therefore you need to make an assumption for the effect of the inner ear canal and this may not be accurate.
OR they can be unblocked, but then there is ENORMOUS positional variation. Even when we were validating the HRTF for the 5128 using in ear mics for example, @Resolve spent a hell of a lot of time just trying to ensure consistency as tiny changes in positioning of the mic can have substantial effects on the measured result.
In-ear mics are a handy tool for EQâing your own headphones on your own head, but you should only treat the stuff below about ~2khz as âaccurateâ. (And again, ONLY in the context of on your own head, not for comparison to other measurements.)
Sounds to complicated for the average joe to be honest.
If there was more demand maybe a Head/torso/ear drum canal taken from your own head and ears using the b&k 5128 tech would be great. But probably cost to much.
Do you think that something like the head from Binural Enthusiasts affixed with a clone mic or 2 be a viable homemade option? My other thought was to verry literally get some kinda in ear mics that i could at least get some form of reference for myself.
I see the value of even measuring ones own gear
For relative measurements for any modding or pad changes and such. Especially for EQ, the value of not just hearing changes, but seeing them, would be incredible for better understanding whats going on. I feel like ive spent enough time woth different gear to makeâŚjust educated guesses.
Would be awesome if gras made something for the masses. I dont measure things, so not sure if one could even effectively make a sort of compensation curve to correlate 2 standardized rigs, so measurements from one could be roughly compared to the other. I feel that even if that could be done between the most recent grass and mini dsp ears, would be huge for the community
But it wouldnât have to be a clone rig if we are compensating to a known rig anyway, right? We could use Resolve as a model for the pinnae and it wouldnât infringe on any IP.
Itâs a common misconception that this kind of thing would be possible. But for the same reason you couldnât just transpose the old Harman target onto the new 5128 with this method, it doesnât work that way (and yes, I am aware there were people who tried to do this⌠those people were wrong).
Two reasons:
Acoustic Z differences - this is going to be rather important for any fixture that doesnât have the same acoustic impedance you get from the 5128. Itâs most relevant for IEMs and closed-back headphones at low and high frequencies, but essentially sound is going to propagate differently and in a way that no single headphone can reliably predict to any sufficient degree. You can get ballpark with low acoustic impedance designs, like with the âunveiledâ series, where this is less of a factor, but you still have to consider that these products will vary in different ways. Even Listenerâs Delta target concept to try to approximate a more accurate result at low frequencies for 711 isnât a sufficiently reliable way to do this because your FR results at low frequencies wonât track consistently.
Differences in headphone behavior across ears in close proximity. I tend to think this more straightforward, but youâll never get a perfect 1:1 match for any given headphone when you place a different ear inside of it, even if acoustic Z is not a factor. We often talk about non-HRTF related HpTF variation, and thatâs really what this is - and the main reason you canât transpose any target or baseline response across rigs. So Iâm not talking about the HRTF effects of each ear being imparted at the DRP, rather the way each headphoneâs behavior is impacted by that ear in close proximity is going to vary, and it doesnât vary in a consistent manner across headphones either.
The bottom line is that you canât really get âequivalent measurementsâ for any rig that is different for any headphone. Now⌠that doesnât mean the same headphone is not comparable across rigs, but youâll still see differences in the FR result.
Maybe Iâm misunderstanding you, but it seems like you are talking about using a single compensation to simulate one rig on another whereas I am proposing that each headphone model would need its own compensation.
Ahhh. So the rig fundementally will measure relative differences (per headphone) that cant be directly correlated between 2 rigs due to fundamental differences of the rigs hrtf that would disallow consistent differences between headphonesâŚis what ive gathered.
So do homemade rigs even offer any legitimate reference?
For instance, using mini dsp ears as a well known prebuilt rig one can obtainâŚwould I be able to draw conclusions measuring the same headphone with lets just sayâŚa pad change, or would the graph of this rig be so unreliable in the trebble that its effectively useless?
That said, i posed my initial question before the most recent noisefloor and am laughing at myself for finding new and confusing ways to over complicate things for myself. Hoping you guys bring some measurement rigs to canjam. Id at least like a better idea of how the actual measuring actually works.
I getcha. I actually think itâs worth entertaining the possibility that if we made a rig based on the anatomy of a single person and acquired a high-quality DF HRTF of said head that we could actually get results that are even closer (for some viewers of the measurement) to what people are hearing than with 5128. I think acquiring a DF HRTF would be more prudent given headphone-specific compensation would entail quite a bit of work, but also only steer the response towards a head (5128) we know to have some meaningful inaccuracy vs the average human response in the treble.
I get the impression from what Oratory1990 has said about the MiniDSP EARS that it is only useful between about 100hz and 1khz. IMHO if you take a before and after measurement on it with a pad swap, I would think that you could still see the broad changes in FR below about 4khz. But you definitely wouldnât want to create a new EQ preset from that.
I have had an EARS rig for years and I still find it useful to volume level between gear. But I donât use it for FR measurements unless a headphone has major issues in the bass or mids that I want to try and EQ (and there is no other source of FR measurement).
Got it. Yeah, seems to be the concensus on the mini ears. Okay. But not great.
Maybe in ear mics is the way to go till the industry starts showing more consistency on rigs in the price range of mini dsp ears.
This option came to my attention as a potential in ear mic to use for this. Im sure the wire wrapped around the ear is less than ideal as it needs to leave the ear cup somewhere which would cause a gap, but maybe not so bad except on my Aeon 2 closed. It would theoretically address my HRTF better, but i doubt these have any consideration for ear canal like a clone GRAS coupler would in a rig.
Iâm not sure I understand the purpose of trying to get the 5128 equivalent of that particular unit? I do think having a more readily available (and cheaper to produce) test fixture based on an individual human ear⌠not a specific standard, would be useful, as long as you had the DFHRTF. Because at the moment we have a lot of rigs pointing at âanatomical standardâ, not âindividual personâ.
